Process of making sodium thiosulfate.



' with the equation WILHJCLill HASENBACH, OF MANNHEIM, GERMANY PROCES$OF MAKING SODIUM THIOSULFATE.

Specification o Letters Patent.

Patented Nov. 3, 3.908.

Original application filed November 1,1907, Serial N o. 400,207. Dividedand. this application filed March 10, 1908.

Serial No. 420,202.

.over solid pulverulent sodium hy rosulfid free from water, when theoxygen is absorbed and thiosulfateformed in accordance It isadvantageous to pass the air over the material at a temperature of 100Centigrade to begin with, and then to raise the temper ature to about150 centigrade. A dry, easily friable roduct is thus prepared which e ofsodium thiosulbe applied in the form in which it was obtained theimpurities with which it is mixed (chiefly finely divided coal) can beremoved by dissolution at the place of its application. By this means, agreat reduction in freight is secured as there is no water ofcrystallization'to be transported.

pulverulent thiosulfate If crystalline thio-sulfate is to be obtainedfrom the reaction product, it is possible, as the product obtainedcontains a large amount of sodium thio-sulfate free from water, toobtain by dissolving the said product in hot water, a lye of suchconcentration as will be suitable for crystallization. This 7 mode ofproceeding has therefore very important advantages over the knownprocesses in which lyes of considerably lower concentration are-obtainedwhich requires a large amount of evaporation. Y

The reaction also takes place when a mixture of sulfureted hydrogen andoxygen in the required proportions is passed over solid pulverulentsodium-sulfid v at a high tern )erature, but in such casepure reactionpro ucts are not obtalned.

I claim:-

The herein described process of manufacturing pulverulent sodiumthiosulfate free from water consisting in passing oxygen in the form ofatmospheric air at a temperature of about to C. over pulverized so--dium hydrosullid free from water. In testimony whereof I have signed-myname to this specification in the presence of two subscribing witnesses.

VVILHELM HASENBAGEL- Witnesses:

ALBERT SoHnLE, Jos. H. LEUTE.

